Gutenberg Leaf


In 2009 Professor Thomas A. Cahill and his wife Virginia (Arnoldy) Cahill (SLU ’64) presented to the Saint Louis University Libraries their leaf from the “42-Line Bible,” believed to have been printed in Mainz, ca. 1454–55, and attributed to Johann Gutenberg. Thought to have been produced in about 180 copies, of which only 48 survive today, this Bible is a large folio volume probably intended not for private reading, but as a lectern Bible for public reading. It is the first book printed from moveable type in Western Europe. Hitherto, all books had been produced by hand—all books were manuscripts. Produced on a printing press, Gutenberg’s Bible is the first mechanically produced book, though it bears many resemblances to its manuscript predecessors.

Biblia Latina. Mainz, 1454–55. Leaf 291r. Acts 10:16–12:2

Biblia Latina. Mainz, 1454–55. Leaf 291v. Acts 10:16–12:2

This leaf is on permanent display in the Archives and Rare Books reading room of Special Collections. Consult Jennifer Lowe, Rare Books Librarian, about arranging a visit (Rm. 307), or to request a class visit and short presentation about the significance of the Gutenberg Bible.

Thomas Cahill became involved with research on the Gutenberg Bible in the 1980s while he was director of the Crocker Nuclear Lab at the University of California, Davis. He, Richard Schwab, and a number of other colleagues applied nuclear physics to history by developing a non-destructive technique of analysis that used a beam of accelerated protons to examine the ink of the Gutenberg Bible. By this means they were able to establish for the first time the chemical composition of the printing ink used by Gutenberg. This ink was and remains extraordinarily glossy and black, thanks to high levels of copper and lead, a formulation known only to Gutenberg and utterly distinct from other printers who followed him in the fifteenth century. Cahill and his colleagues carried out experiments on further copies of the Gutenberg Bible and were able to shed light on their printing process. Their research program became known as the Crocker Historical and Archeological Project, and they went on to apply their method of analysis to other documents, such as the Vinland Map and the Freeman’s Oath. Much of this research has been published in the Papers of the Bibliographical Society of America. Professor Cahill has donated his research papers and data generated from these experiments, and this material is available for consultation.


  • Thomas Cahill is Professor Emeritus of Physics at the University of California, Davis. He was formerly director of the Crocker Nuclear Lab at UC Davis (1980–1989) and is founder and director of the Delta Group for the Detection and Evaluation of the Long-Range Transport of Aerosols at UC Davis, a group that engages in atmospheric testing for the refinement of global climate models. Among other distinctions, he has previously been Director of the Institute of Ecology at UC Davis (1972–1975), Founder and Head of the Air Quality Group at the Crocker Nuclear Laboratory (1970–1997), and designer and principal investigator of US EPA air quality testing for the National Parks and Monuments (1977–1997).
  • Virginia Cahill is a native of St. Louis and a graduate of Saint Louis University. She was Deputy Attorney General for the State of California (2001–2009) and has been a lecturer on water and environmental law at UC Davis since 1993. She has been active in water conservation and environmental issues since 1983. She has been a practicing attorney since 1983 and continues to work on environmental issues. One notable victory in her career was the preservation of water flows out of Mono Lake in California and the restoration of fish populations in its streams. Early in her career she served as assistant editor for a multi-volume inventory of Denis Diderot’s Encyclopédie . Virginia Cahill gave this Gutenberg leaf to her husband in 1985 as a 20th wedding anniversary gift.

Department of Special Collections, Pius XII Memorial Library, Saint Louis University 3650 Lindell Boulevard, St. Louis, MO 63108